On Jan 4, 9:06*pm, wrote:
On Wed, 4 Jan 2012 11:24:25 -0800 (PST), "

wrote:
On Jan 4, 1:49*pm, bob haller wrote:
I wonder how often the solar heater will provide needed heat to the
home.

if may not be cost effective

Another factor is a forced air system frequently already
has a heat exchanger in it, the AC evaporator. *Adding
another obstacle for the air to go through will create
more resistance for the blower. *It might create enough
so that it burns it out the blower motor. *Or the added
resistance reduces the cooling performance in summer,
etc. *Overall, doesn't sound like a great idea to me.

* More resistance won't burn out the blower motor unless it totally
restricts the air-low to the point the motor heat is not removed..

Rducing airflow just makes the blower turn EASIER, not harder.
Try blocking a vacuum hose and listen to the blower SPEED UP.

You do realize there is a difference between a modern
ECM blower motor on a furnace and a vacuum cleaner
that is cavitating, don't you? An ECM motor tries to
maintain constant airflow. Put more resistance on it
and it uses more power to push the air harder. They
are typically spec'd for a maximum pressure. If you
put more resistance in a duct system, be it another
heat exchanger or a clogged filter, you INCREASE
the power used and at some point you decrease
the life of the motor.

Also, furnaces have a min airflow reqt to keep the
heat exchanger within it's correct operating range.
Put more resistance in the duct work and you
could exceed that limit as well.